Potential obscure cathinones that will not vape, but instead massively expand into a feather light powder

I have posted about this before, but now I have received two completely different chems from two vendors months apart that have this characteristic.

One substance was sold as NEP and appeared a white powder with a classic cathinone smell and floury texture. The odor was not like the NEP I've experienced since, that has a sweet almost caramel flavor in addition to a mild cath odor.

This batch would not vape under any circumstances. A small pile would fill a globe halfway with a light voluminous powder that would float out with some vapor and obvious particulate that was air light. Very new vendor.

I decided after storing for a while to wash and crystallize hoping it would help. In fact it is worse, more significant and quick expansion. There is a buzz associated if I inhale any, but it was not very pleasant and harsh. I considered insufflation, not my preferred roa, but decided against it as it seemed a potentially poor choice.

The second chem I received was sent as crystal hexen recently, very dense large rocks, and the rest a small crystalline powder. It was not clear, but pretty cloudy and much more dense than my experience with the chem. Reputable vendor. There was little smell until placed in a jar. After a day, it smelled much like hexen.

Vaping was similar but unique relative to the first chem. It shared almost every aspect, but it would produce more particulate, and tasted almost of citrus. It did also expand in a rapid fashion, but did not stick to the inside of the globe much. A light tap sent the ash/snow like substance out and into the trash. Again, effects were not desirable.

I know there is a term for this reaction, but if anyone has any ideas which cathinones react this way and why, I would be forever grateful. Perhaps it's something simple as a specific residual, or particular salt form.